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<h1 class="RH1">Arccos Function</h1>
<p class="T">Returns the arccosine, or inverse cosine, of a number. The 
arccosine is the angle whose cosine is <i>number</i>. The returned angle is 
given in radians in the range 0 (zero) to <a href="reference_pi.htm">pi</a>.</p>
<p class="RL"><b>Syntax</b></p>
<p class="SYN"><b>arccos</b>(<b>number</b>)</p>
<p class="DT1">Number&nbsp;&nbsp; is any valid
<a href="reference_numeric_expression.htm">numeric expression</a> representing 
the cosine of the angle you want and must be from -1 to 1.</p>
<p class="RL"><b>Remarks</b></p>
<p class="DT1">If your argument is in degrees, multiply it by pi/180 or use the
<a href="reference_radians.htm">radians</a> function to convert it to radians.</p>
<p class="RL"><b>Example</b></p>
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    <th>Expression</th>
    <th>Description (Result)</th>
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    <td>arccos(-0.5)</td>
    <td>Arccosine of -0.5 in radians, 2*pi/3 (2.0944)</td>
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    <td>arccos(-0.5)*180/pi</td>
    <td>Arccosine of -0.5 in degrees (120)</td>
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    <td>degrees(arccos(-0.5))</td>
    <td>Arccosine of -0.5 in degrees (120)</td>
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